This invention relates to a multiple stage absorption refrigeration system and, in particular, to a multiple stage absorption system having the capability of heating water for domestic and other uses.
In many absorption chillers, the heat transfer surfaces are encased in relatively large vessels or shells. Where the absorption system operates near or below atmospheric pressure, the shells are not required to meet safety codes. Multiple stage chillers, however, are now operating at high temperatures and pressures in the upper stages and, as a consequence, the high pressure vessels must meet the safety code requirements, thus increasing the cost of the system.
One option offered to the purchaser of a direct fired absorption system is a domestic hot water condenser wherein hot water is produced using high temperature refrigerant that is generated in the high stage boiler. Because of the pressures involved, the hot water condenser and its associated valves and piping must also meet the ASME code. This, in turn, further raises the cost of the system and, under certain conditions may adversely effect the solution concentration within the system.